Infrared Film-State Measurement on Patterned Substrates
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Solution Overview
Problem
Existing substrate processing methods, particularly in semiconductor manufacturing, face challenges in accurately detecting the state of films formed on substrates with patterns featuring recesses due to interference signals generated by multiple reflections of infrared light, which complicates the analysis of film quality using infrared spectroscopy.
Innovation Solution
A substrate processing method that involves emitting P-polarized infrared light at specific incident angles before and after processing, measuring the transmitted or reflected light, and extracting a difference spectrum to suppress interference signals, allowing for accurate detection of film state and quality on substrates with complex patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If infrared spectroscopy is used to analyze film quality on substrates with patterns featuring recesses, then film composition detection is enabled, but interference signals from multiple reflections complicate the analysis
Solution Approach 1:
The patent changes the incident angle parameter of infrared light to minimize interference signals. By selecting a specific incident angle range (30° to 60°), the multiple reflection interference caused by substrate patterns is reduced, allowing accurate film quality detection without the harmful interference effects
Solution Approach 2:
The patent converts the interference signal problem into a solvable parameter optimization issue. Instead of avoiding the interference entirely, it uses the relationship between incident angle and interference intensity to find optimal measurement conditions where the interference is minimized, transforming the harmful effect into a controllable parameter
2Measurement precision
If P-polarized infrared light is emitted at specific incident angles to reduce interference signals, then measurement accuracy improves, but the complexity of the measurement process increases
Solution Approach 1:
The patent specifies concrete parameter ranges (incident angle of 30° to 60°, P-polarized light) that can be implemented with standard equipment adjustments. This transforms a complex theoretical optimization problem into a practical measurement protocol using readily controllable parameters
Solution Approach 2:
The patent performs preliminary optimization of the incident angle parameter before actual measurement. By pre-determining the optimal angle range based on the substrate pattern characteristics, the measurement process itself becomes simpler and more direct, avoiding the need for complex real-time interference cancellation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces interference signals, enabling precise detection of film composition and quality on substrates with deep recesses, improving the accuracy of film analysis and processing control.
Implementation Method 1
P-polarized infrared light is emitted at a first incident angle onto a substrate
Implementation Method 2
light reflected from the substrate is measured
Implementation Method 3
spectrum indicating the absorbance of infrared light for each wavenumber
Implementation Method 4
an interference signal becomes smaller than a change caused by light absorption by the substrate
Implementation Method 5
interference signals generated by multiple reflections of infrared light
Data Source
AI summary
In a first measuring process, P-polarized infrared light is emitted onto a substrate at a first incident angle at which an interference signal becomes smaller than a change by light absorption by the substrate, and light transmitted through or reflected from the substrate is measured. In a substrate processing process, substrate processing is performed on the substrate after the first measuring process. In a second measuring process, after substrate processing, P-polarized infrared light is emitted onto the substrate at a second incident angle at which an interference signal becomes smaller than a change caused by light absorption by the substrate, and light transmitted through or reflected from the substrate is measured. In an extraction process, a difference spectrum between the spectrum of the transmitted light or reflected light measured in the first measuring process and the transmitted light or reflected light measured in the second measuring process is extracted.